1. Field of the Invention
The present invention relates to a method for fabricating a heating, ventilation and/or air conditioning trunk line adaptor, and more particularly, a method for fabricating a seamless heating, ventilation and/or air conditioning trunk line adaptor which is seamless.
2. Description of the related art including information disclosed under 37 CFR 1.97-1.99
Over the years as construction of buildings evolved, and central convection heating and air conditioning systems were developed, there likewise evolved a need to distribute the heated or cooled air to remote locations within a given building. Conduit systems were constructed to carry the conditioned air from the central heating and/or air conditioning system to the desired locations of the building.
Different rooms in various locations and various distances from the central heating and/or air conditioning system were serviced by the conduit systems. The conduit systems were designed with the concept of constructing larger trunk lines to carry the bulk of the conditioned air through the building and branch conduits were used to carry the conditioned air from these larger trunk lines to discrete room or area locations. The branching of the conduits from larger trunk lines required the branching conduits to be adapted to or connected to the trunk line to carry away conditioned air from the trunk line.
To connect a branching conduit to the main or trunk line, an adaptor was needed to secure the branch conduit to an opening in the main or trunk line. Adaptors typically have a flanged portion with a camber which overlies and conforms to the exterior round main or trunk line surface. The flanged portion defines an opening in the adaptor which communicates with the opening in the trunk line and the flanged portion of the adaptor surrounds the opening in the trunk line. The adaptor includes a conduit portion which communicates with the opening defined by the flanged portion and at the same time communicates with the opening in the trunk line and extends outwardly from the trunk line to engage a branch conduit.
These adaptors were constructed on site or at a remote location by cutting and bending metallic material into two separate pieces to form the flanged and the conduit portion. The flanged portion is cut and bent to the desired shape and is riveted or spot welded together. Another piece of metallic material is cut and bent to form a portion of the conduit which is riveted or welded together into a cylindrical form and, in turn, is riveted or welded to the flanged portion.
The construction of these adaptors, as can be seen, was labor intensive and, in turn, relatively costly. Moreover, the riveted or spot welded securement of the pieces do not permit the adaptors to be air tight. Openings are left between the rivets or spot welds which permits leakage of conditioned air from the system, thereby increasing the cost of heating or cooling of the building.
Unitary or seamless construction of these adaptors has recently become a much desired construction since leakage of conditioned air from the system is substantially prevented. However, it is only known that one other seamless adaptor has been constructed by Air Handling Systems of Woodbridge, Conn. This construction is accomplished by utilizing a single piece of sheet metal being taken by hand from one discrete bending or die station at a time to complete the fabrication. This method does not maximize the reduction of costly labor or maximize the reliability of construction with having manual operations and the human element substantially involved.
Other fabrication or production methods have been used in the past to form seamless manholes for steam boilers as in U.S. Pat. No. 316,312 to J. Tordoff; seamless blocking saddles for steam boilers in U.S. Pat. No. 1,413,492 to Rees; and in the formation of flanges onto tank domes in U.S. Pat. No. 1,493,224 to A. Alston Jr. all of which utilize heat applied to the metal to be worked and none of which uses a series of multiple sequential dies spaced to position a leading segment of a metal strip over the first die of the sequential dies to impart forces upon the leading segment of the strip and then subsequently moving the leading segment of the metal strip to the next die position to impart another force to the leading segment while at the same time a connected trailing segment of the strip is positioned over the first die for experiencing the force imparted by the first die. Consequently, the leading segment of the strip progresses over a sequence of dies changing its shape until the final die imparts the final shape while at the same time the trailing connected segment experiences the forces of the die the leading segment of the strip had just previously experienced. The trailing segment strip progresses through the sequence of dies changing shapes until the final die imparts the final desired shape. Thus, none of these references teach any such progressive die process to be used to form their respective shapes. Moreover, while progressive dies have been utilized in industry, none have appeared to be used in the fabrication of adaptors for trunk lines.